(a) Field of the Invention
This invention generally relates to a system and method for installing and sealing roofing vents. And more particularly, but not by way of limitation, to an air vent for roofing that includes a sliding collar that is adapted to slide down against roofing tiles or shingles and seal around the aperture in the roofing shingles or tiles.
(b) Discussion of Known Art
Modern framed building construction uses wood or metal framed roofs that support layers of roofing material, such as plywood and tar-paper, which is then covered with shingles or tiles. In order to provide appropriate ventilation for the building, ducts that extend from interior portions of the building have to extend through the roofing material and tiles, so that the ducts can vent into the atmosphere. Additionally, roofing vents allow attic air to escape without the aid of additional ducting.
A significant problem associated with extending ducts through roofs is that the aperture through which the duct extends must be sealed to prevent the entry of moisture or other elements, which can deteriorate the underlying roofing materials and damage the structure.
An important problem associated with sealing or isolating the aperture through which the duct extends is that it is time consuming, involving an undesired number of steps that must be carried out by the roofing crew. The larger the number of steps required, the greater the possibility of human error and possibility for leakage. Still further, the greater the number of steps required to install the duct sealing mechanisms, the greater the expense associated with the construction process.
The problem of sealing the roof area becomes particularly acute with roofing vents that require the use of a hood or cap that covers the end of the duct to prevent the entry of rain, snow or other foreign materials. This is because the hood or cap must be of a diameter or cross-section that is larger than the cross-section of the duct extending through the roof.
Thus, there remains a need for a roofing duct or ventilation device that can be easily installed on a roof, without harming or corrupting other components of the roofing system. For example, the duct or ventilation device must be able to cooperate with the roofing felt or waterproofing material as well as a variety of shingle types.
Still further, there remains a need for a device or system that allows the placement of a roofing duct or ventilation device without the need to disassemble and then assemble the roofing duct or device.